Liquid fuel compositions

ABSTRACT

The present invention provides a liquid fuel composition comprising:—a base fuel suitable for use in an internal combustion engine wherein the base fuel comprises oxygenated hydrocarbons; and—one or more polyetheramines having formula (I): wherein R is an —NR 1   2  group where R 1  is independently selected from hydrogen and a C 1 -C 6  hydrocarbyl group, n is in the range of from 6 to 37, m is in the range of from 12 to 74 and p is 0 or 1. The liquid fuel composition provides improved engine cleanliness, improved lubricity and improved fuel economy benefits.

FIELD OF THE INVENTION

The present invention relates to liquid fuel compositions comprising a major portion of a base fuel suitable for use in an internal combustion engine, in particular liquid fuel compositions comprising a major portion of a base fuel suitable for use in an internal combustion engine and a hyperdispersant.

BACKGROUND OF THE INVENTION

Ethanol and methanol are two types of alcohol fuels. The use of pure alcohols in internal combustion engines is possible if the engine is designed or modified for that purpose. Typically, only ethanol is widely used in this manner, particularly since methanol is toxic. Also, in their anhydrous or pure forms, alcohols can be mixed with gasoline in various ratios for use in unmodified gasoline engines, and with minor modifications can also be used with a higher content of alcohol.

Ethanol fuel mixtures have “E” numbers which describe the percentage of ethanol in the mixture by volume. For example, E100 contains 100% ethanol. As another example, E85 is 85% anhydrous ethanol and 15% gasoline. Lower ethanol blends, such as from E5 to E25 are also known. For example, E10 is a fuel mixture of 10% anhydrous ethanol and 90% gasoline that can be used in the internal combustion engines of most modern spark-ignition engines without any need for any modification of the engine or vehicle's fuel system. E10 blends are approved for use in all new U.S. automobiles and are mandated in some places for emissions and other reasons. The E10 blend and lower ethanol content mixtures have been used in several countries and its use has primarily been driven by legislation such as the U.S. Energy Independence and Security Act (EISA) and Directive 2003/39/EC of the European Parliament. U.S. 2009/0307965 A1 discloses a fuel additive concentrate comprising a polyetheramine, antioxidant and a specified friction modifier. The concentrate is proposed for use in a hydrocarbon base fuel or in a blend of ethanol and gasoline having a ratio from 25:75 to 90:10. No technical effect is demonstrated for this combination of additives in either fuel composition.

U.S. Pat. No. 4,518,435 discloses a dispersion of a particulate solid in a polar organic medium utilising a dispersing agent which is a tertiary amine, or salt thereof, the amine containing at least one polymeric group which is a poly(lower alkylene oxy)chain. The particulate solid is suitably selected from organic pigments, organic dyestuffs and carbon black; where an inorganic pigment is used, the polar organic medium is most suitably a lower alkanol. These dispersions find use in the preparation of inks, particularly printing inks for use in package printing. There is no suggestion that such dispersions could be used in or as a fuel composition.

Since alcohol—, e.g. ethanol—and methanol—, based fuels are perceived as clean, pure fuels for the future, it is of importance that such fuels, whether in pure, 100% form, or blended with gasoline should have the look of cleanliness and purity. In Brazil, for example, it is desired that E100 be ‘water-white’. Thus it is important that neither significant discolouration nor significant particulates content be present in alcohol-based fuels.

Colouration has not been a significant concern for fuels to date and additives have been selected for solubility and effect and not for whether use would cause colouration of the resulting fuel formulation. Thus for alcohol-based fuels in general, and for E100 in particular, it is a desire to find additives that have a desired effect without colouration of the final composition.

It has now surprisingly been found that the use of certain polyetheramines in alcohol-based liquid fuel compositions can provide benefits in terms of improved engine cleanliness, improved lubricity, improved fuel economy, and solubility, all without imparting additional colouration to the resulting fuel composition.

SUMMARY OF THE INVENTION

According to the present invention there is provided a liquid fuel composition comprising:

a base fuel suitable for use in a spark ignition internal combustion engine wherein the base fuel comprises oxygenated hydrocarbons; and

one or more polyetheramines having formula (I):

-   wherein R is an —NR¹ ₂ group where R¹ is independently selected from     hydrogen and a C₁-C₆ hydrocarbyl group, n is an integer in the range     of from 6 to 37, m is an integer in the range of from 12 to 74 and p     is 0 or 1.

The compositions of the present invention should not contain added particulate solid such as carbon black.

DETAILED DESCRIPTION OF THE INVENTION

The liquid fuel composition of the present invention comprises a base fuel suitable for use in a spark ignition internal combustion engine and one or more polyetheramines.

The base fuel suitable for use herein comprises one or more oxygenated hydrocarbons.

Examples of oxygenated hydrocarbons that may be incorporated into the base fuel include alcohols, ethers, esters, ketones, aldehydes, carboxylic acids and their derivatives, and oxygen containing heterocyclic compounds. Preferably, the oxygenated hydrocarbons that may be incorporated into the base fuel are selected from alcohols, ethers (preferably ethers containing 5 or more carbon atoms per molecule, e.g., methyl tert-butyl ether) and esters (preferably esters containing 5 or more carbon atoms per molecule).

Particularly preferred oxygenated hydrocarbons for incorporation in the base fuel herein are alcohols, especially alcohols selected from methanol, ethanol, propanol, 2-propanol, butanol, iso-butanol, tert-butanol, 2-butanol and mixtures thereof.

Preferably, the amount of oxygenated hydrocarbons present in the base fuel is selected from one of the following amounts: up to 100% by volume; up to 95% by volume; up to 90% by volume; up to 85% by volume; up to 70% by volume; up to 65% by volume; up to 30% by volume; up to 20% by volume; up to 15% by volume; and, up to 10% by volume, depending upon the desired final formulation of the gasoline. Conveniently, the base fuel may contain at least 0.1, 0.5, 2.0 or 5.0% by volume of oxygenated hydrocarbons.

The polyetheramine used in the present invention may also be referred to as a hyperdispersant.

The one or more polyetheramines in the liquid fuel compositions of the present invention are compounds having formula (I):

-   wherein R is an —NR¹ ₂ group where R¹ is independently selected from     hydrogen and a C₁-C₆ hydrocarbyl group, n is an integer in the range     of from 6 to 37, m is an integer in the range of from 12 to 74 and p     is 0 or 1.

In formula (I), n is preferably in the range of from 8 to 24 and m is preferably in the range of from 16 to 48. In preferred embodiments, the ratio of n:m is 1:2.

In one embodiment of the present invention, p is 1. In another embodiment of the present invention p is 0.

In formula (I), R is a terminal amine group wherein the terminal amine group is selected from —NR¹ ₂, wherein R¹ is selected from hydrogen and a C₁-C₆ hydrocarbyl group.

The R¹ group in the terminal amine group is preferably independently selected from hydrogen and a C₁-C₄ hydrocarbyl group; more preferably R¹ is independently selected from a C₁-C₄ alkyl group. Examples of suitable C₁-C₄ alkyl groups are methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl and t-butyl groups.

Examples of suitable terminal amine groups include —NH₂, —NHCH₃, —NHCH₂CH₃, —NHCH₂CH₂CH₃, —NHCH(CH₃)₂, —NHCH₂CH₂CH₂CH₃, —NHC(CH₃)₃, —N(CH₃)₂, —N(CH₃) CH₂CH₃, —N(CH₃)CH₂CH₂CH₃, —N(CH₂CH₃)₂, —N(CH₂CH₃)CH(CH₃)₂, —N(CH₂CH₃)CH₂CH₂CH₂CH₃, —N(CH₂CH₃)C(CH₃)₃, —N(CH₂CH₃)CH₂CH₃, —N(CH₂CH₃)CH₂CH₂CH₃, —N(CH₂CH₃)CH(CH₃)₂, —N(CH₂CH₃)CH₂CH₂CH₂CH₃, —N(CH₂CH₃)C(CH₃)₃, —N(CH (CH₃)₂)CH₂CH₂CH₃, —N(CH(CH₃))₂, —N(CH (CH₃) ₂)CH₂CH₂CH₂CH₃, —N(CH(CH₃)₂)C(CH₃)₃, —N(CH₂CH₂CH₃)CH₂CH₃, —N(CH₂CH₂CH₃)₂, —N(CH₂CH₂CH₃)CH₂CH₂CH₂CH₃, —N(CH₂CH₂CH₃)C(CH₃)₃, —N(CH₂CH₂CH₂CH₃)₂, —N(CH₂CH₂CH₂CH₃)C(CH₃)₃, and —N(C(CH₃)₃)₂.

In a preferred embodiment of the present invention the terminal amine group is —N(CH₂CH₃)₂. In another preferred embodiment the terminal amine group is —NHCH₂CH₃.

As used herein, the term “hydrocarbyl” represents a radical formed by removal of one or more hydrogen atoms from a carbon atom of a hydrocarbon (not necessarily the same carbon atoms in case more hydrogen atoms are removed).

Hydrocarbyl groups may be aromatic, aliphatic, acyclic or cyclic groups. Preferably, hydrocarbyl groups are aryl, cycloalkyl, alkyl or alkenyl, in which case they may be straight-chain or branched-chain groups.

In the present invention, the phrase “optionally substituted hydrocarbyl” is used to describe hydrocarbyl groups optionally containing one or more “inert” heteroatom-containing functional groups. By “inert” is meant that the functional groups do not interfere to any substantial degree with the function of the compound.

The preparation of compounds of formula (I) is known and is described in the art, for example in WO96/00440.

Examples of polyetheramines suitable for use herein include CH-10S commercially available from Shanghai Sanzheng Polymer Material Co. Ltd (China) and Solsperse (RTM) 20000 commercially available from Lubrizol Advanced Materials Inc.

The base fuel may comprise a gasoline fuel in addition to the oxygenated hydrocarbons. Preferably, the amount of gasoline present in the base fuel is selected from one of the following amounts: up to 99.9%, up to 99.5%, up to 99%, up to 98%, up to 95%, and at least 5%, at least 10%, at least 30%, at least 35%, at least 70%, at least 75%, at least 80%, at least 90%, by volume of the base fuel.

In the liquid fuel compositions of the present invention, if the base fuel comprises a gasoline, then the gasoline may be any gasoline suitable for use in an internal combustion engine of the spark-ignition (petrol) type known in the art. The gasoline used as base fuel in the liquid fuel composition of the present invention may conveniently also be referred to as ‘base gasoline’.

Gasolines typically comprise mixtures of hydrocarbons boiling in the range from 25 to 230° C. (EN-ISO 3405), the optimal ranges and distillation curves typically varying according to climate and season of the year. The hydrocarbons in a gasoline may be derived by any means known in the art, conveniently the hydrocarbons may be derived in any known manner from straight-run gasoline, synthetically-produced aromatic hydrocarbon mixtures, thermally or catalytically cracked hydrocarbons, hydro-cracked petroleum fractions, catalytically reformed hydrocarbons or mixtures of these.

The specific distillation curve, hydrocarbon composition, research octane number (RON) and motor octane number (MON) of the gasoline are not critical.

Conveniently, the research octane number (RON) of the gasoline may be at least 80, for instance in the range of from 80 to 110, preferably the RON of the gasoline will be at least 90, for instance in the range of from 90 to 110, more preferably the RON of the gasoline will be at least 91, for instance in the range of from 91 to 105, even more preferably the RON of the gasoline will be at least 92, for instance in the range of from 92 to 103, even more preferably the RON of the gasoline will be at least 93, for instance in the range of from 93 to 102, and most preferably the RON of the gasoline will be at least 94, for instance in the range of from 94 to 100 (EN 25164); the motor octane number (MON) of the gasoline may conveniently be at least 70, for instance in the range of from 70 to 110, preferably the MON of the gasoline will be at least 75, for instance in the range of from 75 to 105, more preferably the MON of the gasoline will be at least 80, for instance in the range of from 80 to 100, most preferably the MON of the gasoline will be at least 82, for instance in the range of from 82 to 95 (EN 25163).

Typically, refinery gasolines comprise components selected from one or more of the following groups; saturated hydrocarbons, olefinic hydrocarbons and aromatic hydrocarbons. Conveniently, the gasoline may comprise a mixture of saturated hydrocarbons, olefinic hydrocarbons and aromatic hydrocarbons.

Typically, the olefinic hydrocarbon content of the gasoline is in the range of from 0 to 40 percent by volume based on the gasoline (ASTM D1319); preferably, the olefinic hydrocarbon content of the gasoline is in the range of from 0 to 30 percent by volume based on the gasoline, more preferably, the olefinic hydrocarbon content of the gasoline is in the range of from 0 to 20 percent by volume based on the gasoline.

Typically, the aromatic hydrocarbon content of the gasoline is in the range of from 0 to 70 percent by volume based on the gasoline (ASTM D1319), for instance the aromatic hydrocarbon content of the gasoline is in the range of from 10 to 60 percent by volume based on the gasoline; preferably, the aromatic hydrocarbon content of the gasoline is in the range of from 0 to 50 percent by volume based on the gasoline, for instance the aromatic hydrocarbon content of the gasoline is in the range of from 10 to 50 percent by volume based on the gasoline.

The benzene content of the gasoline is at most 10 percent by volume, more preferably at most 5 percent by volume, especially at most 1 percent by volume based on the gasoline.

The gasoline preferably has a low or ultra low sulphur content, for instance at most 1000 ppmw (parts per million by weight), preferably no more than 500 ppmw, more preferably no more than 100, even more preferably no more than 50 and most preferably no more than even 10 ppmw.

The gasoline also preferably has a low total lead content, such as at most 0.005 g/l, most preferably being lead free—having no lead compounds added thereto (i.e. unleaded).

Preferably the gasoline for use herein is a reformulated blendstock for oxygenate blending (an RBOB).

Examples of suitable gasolines include gasolines which have an olefinic hydrocarbon content of from 0 to 20 percent by volume (ASTM D1319), an oxygen content of from 0 to 5 percent by weight (EN 1601), an aromatic hydrocarbon content of from 0 to 50 percent by volume (ASTM D1319) and a benzene content of at most 1 percent by volume.

Whilst not critical to the present invention, the liquid fuel composition of the present invention may conveniently additionally include one or more fuel additive(s). The concentration and nature of the fuel additive(s) that may be included in the liquid fuel composition of the present invention is not critical. Non-limiting examples of suitable types of fuel additives that can be included in the liquid fuel composition of the present invention include anti-oxidants, corrosion inhibitors, detergents, dehazers, antiknock additives, metal deactivators, valve-seat recession protectant compounds, dyes, friction modifiers, carrier fluids, diluents and markers, though preferably no dyes or coloured markers are used in the compositions of the present invention. Examples of suitable additives are described generally in U.S. Pat. No. 5,855,629.

In one embodiment the polyetheramine of formula (I) is used in conjunction with a detergent fuel additive. Detergents for use herein may be any detergent suitable for use in a fuel composition. Suitable detergents for such use include polyisobutyleneamine detergents.

Conveniently, the fuel additives can be blended with one or more diluents or carrier fluids, to form an additive concentrate, the additive concentrate can then be admixed with the base fuel of the present invention.

The polyetheramines of formula (I) may be added to the fuel composition as part of the additive concentrate or may be added direct to the base fuel at the same time as or at a different time to an additive or additive concentrate, if used.

The (active matter) concentration of any additives present in the base fuel of the present invention is preferably up to 1 percent by weight, more preferably in the range from 5 to 1000 ppmw, advantageously in the range of from 75 to 300 ppmw, such as from 95 to 150 ppmw.

In the above, amounts (concentrations, % vol, ppmw, % wt) of components are of active matter, i.e. exclusive of volatile solvents/diluent materials.

The liquid fuel composition of the present invention is produced by admixing the one or more polyetheramines of formula (I) with a base fuel suitable for use in an internal combustion engine.

Preferably, the amount of the one or more polyetheramines of formula (I) present in the liquid fuel composition of the present invention is at least 1 ppmw (part per million by weight), based on the overall weight of the liquid fuel composition. More preferably, the amount of the one or more polyetheramines present in the liquid fuel composition of the present invention additionally accords with one or more of the parameters (i) to (xx) listed below:

(i) at least 10 ppmw

(ii) at least 20 ppmw

(iii) at least 30 ppmw

(iv) at least 40 ppmw

(v) at least 50 ppmw

(vi) at least 60 ppmw

(vii) at least 70 ppmw

(viii) at least 80 ppmw

(ix) at least 90 ppmw

(x) at least 100 ppmw

(xi) at least 1000 ppmw

(xii) at most 20% wt.

(xiii) at most 18% wt.

(xiv) at most 16% wt.

(xv) at most 14% wt.

(xvi) at most 12% wt.

(xvii) at most 10% wt.

(xviii) at most 8% wt.

(xix) at most 6% wt.

(xx) at most 4% wt.

(xxi) at most 2% wt.

Conveniently, the amount of the one or more polyetheramines of formula (I) present in the liquid fuel composition of the present invention may also be at least 200 ppmw, at least 300 ppmw, at least 400 ppmw, at least 500 ppmw, or even in certain embodiments at least 1000 ppmw.

In one embodiment the amount of polyetheramine of formula (I) is in the range of from 10 ppmw, suitably 100 ppmw, to 1000 ppmw, most suitably from 300 ppmw to 700 ppmw, preferably 400 to 600 ppmw and especially 500 ppmw, based on total fuel composition.

It has surprisingly been found that the use of the one or more polyetheramines of formula (I) in liquid fuel compositions can also provide benefits in terms of improved fuel economy of an internal combustion engine being fuelled by the liquid fuel composition of the present invention, relative to the internal combustion engine being fuelled by the liquid base fuel.

The present invention therefore provides a method of improving the fuel economy performance of a liquid base fuel suitable for use in an internal combustion engine, comprising admixing one or more polyetheramines of formula (I) with a major portion of the liquid base fuel suitable for use in an internal combustion engine.

It has additionally been observed that the use of the one or more polyetheramines of formula (I) in the liquid fuel compositions of the present invention can provide significant benefits in terms of improved lubricity of the liquid fuel composition, relative to the liquid base fuel.

By the term “improved/improving lubricity” used herein, it is meant that the wear scar produced using a high frequency reciprocating rig (HFRR) is reduced.

It has further been observed that the use of the one or more polyetheramines of formula (I) in liquid fuel compositions can also provide benefits in terms of engine cleanliness, in particular in terms of improved inlet valve deposit keep clean and/or injector nozzle keep clean performance, of an internal combustion engine being fuelled by the liquid fuel composition of the present invention relative to the internal combustion engine being fuelled by the liquid base fuel.

Engine cleanliness can be further enhanced by the use of a polyetheramine of formula (I) in combination with a detergent fuel additive. The combined use in a fuel composition of the present invention appears to act synergistically to provide a greater enhanced engine cleanliness than would be achieved by the use of either component alone. It has further been observed that use of a polyetheramine of formula(I) in the fuel composition of the present invention appears to lead to diffused fuel residues and thereby reducing the likelihood that fuel deposits will form in use for example on engine valves. This diffusion of residue deposits is observed whether the polyetheramine is used alone in the composition or in combination with a detergent fuel additive.

When used in combination with a detergent fuel additive, the amount of polyetheramine in the fuel composition is suitably in the range of from 50 ppmw to 500 ppmw, most suitably from 50 ppmw 300 ppmw, for example 100 to 200 ppmw, based on total fuel composition. The amount of a detergent fuel additive is suitably in the range of from 100 ppmw to 500 ppmw, suitably 250 to 500 ppmw, based on the total fuel composition.

By the term “improved/improving inlet valve deposit keep clean performance”, it is meant that the weight of deposit formed on the inlet valve of the engine is reduced relative to the base fuel not containing the one or more polyetheramines of formula (I).

By the term “improved/improving injector nozzle keep clean performance”, it is meant that the amount of deposit formed on the injector nozzle of the engine is reduced as measured by the loss of engine torque.

In contrast to other dispersants, the polyetheramines used in the present invention have furthermore been found to be fully soluble in alcohol-based fuel compositions, especially E100 compositions, and impart no colour or haze to the final formulation.

The present invention further provides a method of operating an internal combustion engine, which method involves introducing into a combustion chamber of the engine a liquid fuel composition according to the present invention.

The present invention will be further understood from the following examples. Unless otherwise stated, all amounts and concentrations disclosed in the examples are based on weight of the fully formulated fuel composition.

EXAMPLES Examples 1 to 8

Ethanol and gasoline were mixed according to the weight ratios set out in Table 1 below. Suitable amounts of detergent and CH-10S (a polyetheramine commercially available from Shanghai Sanzheng Polymer Material Co. Ltd (China)) were added to the base fuel as set out in Table 1 below.

The formulations of the present invention provide benefits in terms of improved engine cleanliness as well as improved fuel economy.

TABLE 1 Example: 1 2 3 4 5 6 7 8 Base Fuel Ethanol (wt %) 93 85 70 10 93 85 70 10 Composition: Water (wt %) 7 0 0 0 7 0 0 0 Gasoline (wt %) 0 15 30 90 0 15 30 90 Detergent (ppmw) 500 500 500 500 250 250 250 250 CH-10S (ppmw) 100 100 100 100 100 100 100 100 

1. A liquid fuel composition comprising: (a) a base fuel suitable for use in an internal combustion engine wherein the base fuel comprises oxygenated hydrocarbons; and (b) one or more polyetheramines having formula (I):

wherein R is an —NR¹ ₂ group where R¹ is independently selected from hydrogen and a C₁-C₆ hydrocarbyl group, n is in the range of from 6 to 37, m is in the range of from 12 to 74 and p is
 1. 2. The fuel composition of claim 1, wherein the oxygenated hydrocarbons are alcohols.
 3. The fuel composition of claim 2, wherein the alcohols are selected from the group consisting of ethanol, methanol, propanol, 2-propanol, butanol, 2-butanol, iso-butanol, tert-butanol, and mixtures thereof.
 4. The fuel composition of claim 3, wherein the alcohol is ethanol.
 5. The fuel composition of claim 1, wherein the base fuel comprises at most 100% by volume of oxygenated hydrocarbons.
 6. The fuel composition of claim 1, wherein the base fuel comprises at most 85% by volume of oxygenated hydrocarbons.
 7. The fuel composition of claim 1, wherein the base fuel further comprises gasoline.
 8. The fuel composition of claim 7, wherein the base fuel comprises at least 15% by volume of gasoline.
 9. The fuel composition of claim 1 further comprising a detergent.
 10. The fuel composition of claim 1, wherein the amount of the one or more polyetheramines present in the liquid fuel composition is in the range of from 10 ppmw to 1000 ppmw, based on the overall weight of the liquid fuel composition.
 11. The fuel composition of claim 1, wherein R¹ is independently selected from a C₁-C₄ alkyl group.
 12. A method of operating an internal combustion engine comprising (a) introducing into a combustion chamber of the engine a liquid fuel composition of claim 1; and (b) operating said fuelled internal combustion engine.
 13. (canceled)
 14. (canceled)
 15. (canceled)
 16. The composition of claim 11 wherein the terminal amine group is —N(CH₂CH₃)₂.
 17. The composition of claim 1 wherein the terminal amine group is —NHCH₂CH₃. 